I don't know. ... ...... It is a slight hassle, but you can prepare shipping labels (and get a small discount) at the US Post Office's Click-N-Ship. For example, you can send a 2 ounce FIRST CLASS INTERNATIONAL PARCEL for $6.16. They even let you maintain an address book with them. No extra charges. If these links don't help, just do a search for Click and Ship at post office site:

https://www.usps.com/business/business-shipping.htm
https://cns.usps.com/labelInformation.shtml

Here is what part of their form looks like for a 2 ounce package sent to Netherlands:

Robert